THE POPLITEAL ARTERY 281 



(d) The plantar digital passes between the heads of the first 

 dorsal interosseous, joins with the external plantar to form the 

 plantar arch, and after supplying the inner -side of the great 

 toe divides into two branches for the adjacent sides of the 

 great and second toes. 



The posterior tibial artery runs from the lower border of the 

 popliteus to divide, between the inner malleolus and heel, into 

 the external and internal plantar arteries. 



Relations. In front, tibialis posticus, flexor longus digitorum, 

 tibia, and ankle joint; behind, skin, fascia, gastrocnemius, soleus, 

 deep transverse fascia, posterior tibial nerve. This nerve is 

 internal in its upper part, but lower down it is external to the 

 artery. 



Its branches are: 



(a) The peroneal runs from one inch below the popliteus to the 

 lower third of the leg, and divides into the anterior and posterior 

 peroneal. It is covered by the soleus and deep transverse fascia ; 

 in front of it are the tibialis posticus and interosseous membrane; 

 external to it, the fibula; and externally, as well as behind, the 

 flexor longus pollicis. 



The peroneal gives off muscular branches and a nutrient artery 

 to the fibula. The anterior peroneal passes beneath the inter- 

 osseous membrane to the front of the leg, and runs to the outer 

 ankle to join the tarsal and external malleolar. The posterior 

 peroneal passes down behind the external malleolus, and termi- 

 nates in branches (external calcaneal) which anastomose with 

 the external malleolar. 



(6) The nutrient artery for the tibia. 



(c) The muscular branches. 



(d) The communicating. 



(e) Several internal malleolar. 



The plantar arteries are the terminal branches of the posterior 

 tibial. The internal is at first under cover of the abductor 

 pollicis, and then between it and the flexor brevis digitorum, 

 anastomosing at the inner border of the great toe with its 

 digital artery. 



The external, the larger, passes to the base of the fifth meta- 

 tarsal, then to the space between the first and second meta- 

 tarsals, and joins the plantar digital, from the dorsalis pedis, 

 to form the plantar arch. 



The plantar arch supplies the muscles, fascia, and skin of the 



